QJson*: value semantics cleanup

Re-add the move operations, add a swap(), mark as shared
(we're already using them in containers).

QJsonValue is slightly tricky, because it has an anonymous union,
which can't be easily moved in C++. Use the implementation of
the copy constructor as inspiration for the move.

[ChangeLog][QtCore][JSON] QJsonArray, QJsonDocument, QJsonObject
and QJsonValue now have move operations and a swap() member function.

Change-Id: Idfb94a93370ace96100efbd6559ef05b4c5adc39
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/corelib/json/qjsondocument.cpp b/src/corelib/json/qjsondocument.cpp
index ed454d5442..d1169d90e3 100644
--- a/src/corelib/json/qjsondocument.cpp
+++ b/src/corelib/json/qjsondocument.cpp
@@ -153,6 +153,28 @@ QJsonDocument &QJsonDocument::operator =(const QJsonDocument &other)
     return *this;
 }
 
+/*!
+    \fn QJsonDocument::QJsonDocument(QJsonDocument &&other)
+    \since 5.10
+
+    Move-constructs a QJsonDocument from \a other.
+*/
+
+/*!
+    \fn QJsonDocument &QJsonDocument::operator =(QJsonDocument &&other)
+    \since 5.10
+
+    Move-assigns \a other to this document.
+*/
+
+/*!
+    \fn void QJsonDocument::swap(QJsonDocument &other)
+    \since 5.10
+
+    Swaps the document \a other with this. This operation is very fast and never fails.
+*/
+
+
 /*! \enum QJsonDocument::DataValidation
 
   This value is used to tell QJsonDocument whether to validate the binary data